Project Wise-Pac:  Sensor Networks for Medical Applications

Wireless Sensor Systems for the Medical Ward of the 21st Century

In the spring of 2005, The University of Calgary and the Calgary Health Region (CHR) embarked on a new joint initiative to design new technologies to be tested in the CHR hospital system. A July 5, 2005 press release reads as follows:

"The University of Calgary and the Calgary Health Region today announced a partnership to research and develop new concepts and technologies that will improve patient care and create safer health care environments with a new generation of wireless medical devices that will eventually be “built in” to the Region’s new South Health Campus.

This unique partnership between frontline healthcare workers and electrical and computer engineers at the University of Calgary’s newly created Calgary Centre for Engineered Care vaults the University and Region into the forefront of healthcare technology. “New techniques and devices created by these teams will have a direct impact on patient safety,” said Dr. John Conly, Regional Clinical Department Head of Medicine, Calgary Health Region and the U of C’s Faculty of Medicine. “Innovations such as systems and sensors capable of real-time monitoring of vital signs and movement, on-demand drug delivery systems and continuous blood and fluid analysis will be built into the Region’s South Health Campus and future health care facilities.”

The Calgary Centre for Engineered Care brings together a multi-disciplinary team of researchers from science, engineering and medicine. The Centre was created to help facilitate their work and accelerate collaboration between the University and Region.

“This area of research is truly exciting, considering the potential benefits to the partners and the patients,” said Dr. Josh Leon, Head of the Department Electrical and Computer Engineering in the U of C’s Schulich School of Engineering. “Improving quality of life for Albertans, demonstrating research leadership and creating potential commercial spin-offs are all positives that will come from this partnership.”

New technologies include:

As the new technologies are further developed, they will be thoroughly tested on the Medical Ward of the 21st Century, Unit 36 at the Foothills Medical Centre."

Our research group is designing the wireless "smart bandaids"  that will allow wireless monitoring of patient vital signs in the new Medical Ward of the 21st Century that has been constructed at Foothills Hospital in Calgary. The heart of the sensing system is a circuit called a "wireless sensor platform for acquisition and control"(Wise-Pac), which consists of an A/D converter, microcontroller, ultra low power wireless transceiver and integral antenna system, power scavenging circuitry and thin battery technology that will have the appearance of a bandaid, and will include new sensor technologies and attach directly to various parts of the body to monitor vital signs such as body core temperature, respiratory rate, heart rate and EKG, and eventually blood pressure and blood gas concentrations.

First generation devices have been designed and fabricated using commercial motes, and a temperature measuring smart bandaid was demonstated in July of 2005.  The device is shown below:

Stephanie

The first generation devices were bulky and power hungry when transmitting continuously, and body temperature measurement was achieved using an off body ambient temperature measurement as a reference. A new system is currently being designed to overcome the power consumption problems, to reduce the bulky nature of the system, and to remove the need for an ambient measurement. The anatomy of the next generation device is shown below:

Explodeed Bandage

The band aid consists of the following layers:

The target for this next generation device is to achieve operation for weeks at a time on a low cost battery, while transmitting at data rates of hundreds of bits per second continuously, so that nursing staff will not have to change batteries once the device is attached to a patient.
The sensor array used to measure body temperature is critical to the success of the device. A patent has been filed on the new measurement technique, which is embedded in the bandaid at the temple as shown below.




Bandage on Head

A working prototype demonstrates proof of concept of the system, and initial trials suggest that accurate body temperature readings are achievable with the new sensor scheme.  A third generation prototype is being constructed, using flexible circuit board. Layout is shown below.




In the longer term, a single chip platform is being designed, to reduce cost and which will result in a disposable device to avoid hygeine issues associated with reusable devices.

The research team represents a multi-disciplinary (MEMS, wireless, IC design, security, signal processing and medicine) group of researchers with the expertise and track record needed to accomplish the project. The team is outlined below.

   Some of our recent publications relating to the studies of low power systems for these applications are listed below:

  1. Townsend, K., J. Haslett, T. K. K. Tsang, M. N. El-Gamal, and K.Iniewski, “Recent Advances and Future Trends in Low Power Wireless Systems for Medical Applications”, 
    presented at the 5th IEEE International Workshop on System-on-Chip for Real-Time Applications, July 2005, Banff, Alberta.
  2. Tsang, T. K. K., M. N. El-Gamal, K. Iniewski, K. Townsend, and J. Haslett,  “Current Status and Trends of CMOS Low Voltage Low Power Wireless IC Designs”, 
    presented at the 3rd International IEEE Northeast Workshop on Circuits and Systems (NEWCAS), Quebec City, June 2005.
  3. Johnston, R.H. and J.W. Haslett, “Antennas for RF Mote Applications”, presented at the 2005 IEEE AP-S International Symposium on Antennas and Propagation, 
    Washington
    DC
    , July 2005.
  4. C. Siu1, S. Kasnavi1, K. Iniewski, F. Nabki, M. El-Gamal, K. Townsend, J. Haslett, "RF CMOS Circuits for Ad-Hoc Networks and Wearable Computing", Proceedings of the 2005 8th Euromicro conference on Digital System Design (DSD’05) 0-7695-2433-8/05, 2005.
  5. Finvers, I., J.W. Haslett and G.A. Jullien, " Wireless Temporal Artery Thermometer", accepted for publication at BioCAS 2006, UK, November 2006.




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